This type of wheelchair is known from CA 2 458 122 A1 or DE 199 12 830. The constant seated position of the user leads to degradation of bodily functions over long periods of time, such as reduced movement of the lower extremities, deceleration of intestinal activity and the impairment of blood circulation. Sitting also increases the risk of decubitus ulcers. A standing wheelchair aids in reducing these consequences through changes in body position, up to a standing position, which reduces the degradation of bodily functions. The movable seat surface is mounted on a chassis frame with backrest and foot supports. The correct adjustment to the anatomical requirements of the user is a very important criterion for comfort, which the wheelchair offers. Through this, the relation of seat depth and lower leg as well as upper leg to the position of the footrest is determined using the body measurements of the user. In accordance with the dimensions provided, a standing wheelchair is selected from the standard manufacturer program and produced.
User specific manufactured wheelchairs often provide unsatisfactory comfort for small and large people, because the standardized sizes of the standing wheelchairs are based on average body sizes. Often, the lack of adjustment is only indirectly perceived by the user. Friction movement between the body and the seat or an overly strong surface pressure from the kneepads can lead to decubitus ulcers in a short period of usage time. If the seat is adjusted, the angle of the seat is changed in the known wheelchairs, which is uncomfortable.
Standing wheelchairs offer the user the option to participate in sports activities. Thus the user can play golf, for example. In these cases it is particularly important that the wheelchair offer a high degree of stability in the upright position. Thus there is a requirement that the foot supports stand on the floor in the upright position and are supported by it. The backrest must be parallel to the seat and the golfer must have sufficient freedom of movement (turning of the upper body) in order to be able to swing a club.
In such a case, standing wheelchairs are often kept at the ready at golf courses and used by various users. Wheelchairs designed for people of average size can be used by a range of disabled persons only under great loss of comfort, because the seat height is not optimally adjustable.
From CA 2 458 092, an adjustable wheelchair is known. The seat depth can be changed by an adjustable backrest. The backrest is telescoping and connected to the lower chassis of the seat. The telescoping rods are not particularly functional in practical use. In order to guarantee stability, low tolerances are required. Frequent adjustment leads to wear and tear. The bilateral telescoping rods under the seat can tilt toward each other. The backrest is then not straight in relation to the seat and secure uplift of the wheelchair is not possible. Telescoping rods also collect dirt, which is unavoidable during sports activities.
EP 1 413 278 A1 publishes a wheelchair, in which the seat is adjustable in height via a jointed parallelogram, which is pivotable. With the change of the seat height, the position of the seat in the direction of travel is also changed. According to the configuration of the parallelogram, the seat is repositioned either forward or backward when in motion.